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Direct-injection spark-ignition (DISI) engines have been investigated for many years but only recently have shown promise as a next generation gasoline engine technology. Much of this new enthusiasm is due to advances in the fuel injection system, which is now capable of producing a well-controlled spray with small droplets. A physical understanding of new combustion systems utilizing this technology is just beginning to occur. This analytical and experimental investigation with a research single-cylinder combustion system shows the benefits of in-cylinder gasoline injection versus injection of fuel into the intake port. Charge cooling with direct injection is shown to improve volumetric efficiency and reduce the mixture temperature at the time of ignition allowing operation with a higher compression ratio which improves the thermodynamic cycle efficiency.

A rotary heat exchanger may be mounted at either the hub or the rim. In either case, the mounting system must be capable of thousands of hours of operation, unlubricated, and in a highly oxidizing environment at temperatures in excess of 250°C (482°F). The development of both a hubmounted and a rim mounted system is described in this paper, and pertinent test results in the solution of durability problems peculiar to each system are reviewed. These results are based on over 300,000 hours of turbine engine test experience on rotary ceramic heat exchangers.